title: Mechanisms associated with the variation in tenderness of meat from Brahman and Hereford cattle.
abstract: To study possible mechanisms for differences in meat tenderness, 10 purebred Hereford and 10 American Grey Brahman steers were fed a typical feedlot diet and slaughtered when ultrasound measurements indicated that they had approximately 1 cm of fat thickness at the 12th rib. Longissimus muscle from Brahman cattle was less (P less than .05) tender after 7, 14, 21, 28 and 35 d postmortem than muscle from Hereford cattle, but muscle from Hereford cattle showed greater improvement in tenderness from 7 to 14 d postmortem than muscle from Brahman cattle (interaction P less than .05). Cathepsin B or cathepsin B+L activities and the myofibrillar response to elevated ionic strength were not different between breeds, but both could be related to the postmortem increase in tenderness of both breeds. Calcium-dependent protease activity, as modulated by calcium-dependent protease inhibitor, seems to play a major role in the inherent tenderness differences between breeds.
authors.affiliation: Texas Agricultural Experiment Station, Texas A&M University, College Station 77843-2471.
authors.forename: T L
authors.initials: TL
authors.lastname: Wheeler
authors.forename: J W
authors.initials: JW
authors.lastname: Savell
authors.forename: H R
authors.initials: HR
authors.lastname: Cross
authors.forename: D K
authors.initials: DK
authors.lastname: Lunt
authors.forename: S B
authors.initials: SB
authors.lastname: Smith
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology; D000818:Animals; D001947:Breeding; D002417:Cattle / Q000033:anatomy & histology* / Q000235:genetics; D010450:Endopeptidases / Q000032:analysis; D006863:Hydrogen-Ion Concentration; D008297:Male; D008460:Meat / Q000592:standards*; D008854:Microscopy, Electron; D009124:Muscle Proteins / Q000378:metabolism; D009132:Muscles / Q000196:embryology / Q000378:metabolism / Q000648:ultrastructure; D011180:Postmortem Changes; D011480:Protease Inhibitors / Q000032:analysis; D012995:Solubility; D013696:Temperature
chemical_list: D009124:Muscle Proteins; D011480:Protease Inhibitors; D010450:Endopeptidases